This invention relates generally to electrical contacts and techniques for the making the same and particularly to techniques for making electrical contacts for microelectronic devices such as integrated circuit devices and contacts utilized with such devices.
A variety of devices are known for making Z-axis electrical contacts. By xe2x80x9cZ-axisxe2x80x9d it is intended to refer to an element which extends transversely to the plane of the surface or surfaces to be contacted. One advantage of Z-axis contacts is that they accommodate for irregularities in one or more surfaces being contacted.
Metallic paste for forming electrical contacts has been known for some time. For example, solder pastes include conductive particles in a flux matrix. However, solder pastes have little ability to provide Z-axis connections because once heated they generally have little or no structural integrity.
In a variety of modern electronic packaging used for integrated circuits and other microelectronic devices, a plurality of contacts on one electrical component may be situated on contacts on another electrical component. In the presence of heat, the contacts on one component may melt or soften sufficiently to connect them to components on the other device. Many of these connectons are advantageous because they occur in regions which could not be accessed otherwise. For example, surface mount packages and ball grid arrays may use this type of connection.
While these products may use conductive bumps, these bumps generally cannot accommodate for a variety of irregularities which may be encountered by contacts. One problem faced with conventional contacts is that a good electrical connection may not be possible between two contacts because a native oxide film has formed over one or more of the contacts which prevents the electrical connection. Another difficulty, described above, is that the contacting surfaces often are irregular so that good physical connection is not always possible.
Thus, there is a continuing need for a Z-axis contact which facilitates connection between surfaces which may be irregular, which improves the connection in a variety of surfaces, and which at least in some cases, facilitates connection between surfaces which may be occluded by a native oxide layer.
In accordance with one aspect of the present invention, an electrical contact for a microelectronic device includes a first contact pad and a resinous member having conductive particles. The member extends upwardly from the first contact pad.
In accordance with another aspect of the present invention, an electrical connection for a microelectronic device includes a first contact pad and a resinous member having conductive particles dispersed through the member. The resinous member has upper and lower ends. A second contact pad is connected to the upper end of the member and the first contact pad is connected to the lower end of the member.
In accordance with yet another aspect of the present invention, an electrical contact for a semiconductor device includes an annular member formed of conductive particles in a resinous matrix. The member is adapted to physically and electrically connect to conductive terminations.
In accordance with another aspect of the present invention, a method of electrically contacting a surface includes the step of depositing an annular member formed of conductive particles in a resinous matrix. The member is physically connected between a pair of conductive surfaces.
In accordance with but another aspect of the present invention, a method of making electrical contact includes the step of forming an upstanding conductive, annular member on a first contact surface. The member contacts a second contact surface. The member is heated to bond the member to the second contact surface.
In accordance with yet another aspect of the present invention, a stencil for forming a deposit for making electrical contact includes an annular opening formed in the stencil. At least one bridge element spans across the annular opening.
In accordance with another aspect of the present invention, a method of forming a deposit in making semiconductor devices includes the step of forming at least one annular opening in a plate to form an inner member inward of the opening and an outer member outward of the opening. A physical connection is maintained between the inner and outer members.
In accordance with but another aspect of the present invention, a resinous electrically conductive material includes a resinous body having an edge surface. A plurality of electrically conductive particles lap one another along the edge surface so as to form an electrically conductive path along the edge surface.